1. Field of the Invention
This invention pertains to high-speed conveyors, and more particularly, to conveyors of the type used in conjunction with a strapping machine especially where the strapping machine is strapping unstable articles such as stacks of newspaper and compacting the stacks at a strapping location on the strapping machine.
2. Description of the Prior Art
Strapping machines heretofore known have been unable to move stacks of paper through the strapping station of the machine at very high speeds. One of the reasons is the fact that the stack of newspapers is very unstable requiring that it be accelerated and decelerated slowly. One attempt to provide more stability to the stack has been to place a spring biased wheel on the top of the stack to hold the stack tightly against the lower conveying surface. Another technique has been to place a second conveyor on the top of the stack and to attempt to drive both of the conveyors synchronously at the same acceleration rates. Neither of these techniques has proven successful.
Another difficulty with strapping machines is that the compactor beam for compressing the stack has always been a cumbersome mechanism requiring either long stroke cylinders sticking up above the conveyor or extending down into the strapping mechanism below the conveyor in order to provide sufficient stroke to move the compacting beam all the way to the surface of the conveyor as is necessary where only a few papers exist in the stack. Furthermore, these cylinders frequently get out of synchronism with one another such that the compactor beam ends will not come down synchronously and an improper compaction occurs.